如何创建一个黑色的UIImage？ [英] How to create a black UIImage?

问题描述

我已经四处张望，但我找不到办法。我需要创建一个黑色的UIImage一定的宽度和高度（宽度和高度的变化，所以我不能只创建一个黑盒子，然后将其加载到UIImage）。有没有办法做一个CGRect，然后将其转换为UIImage？

I've looked around everywhere, but I can't find a way to do this. I need to create a black UIImage of a certain width and height (The width and height change, so I can't just create a black box and then load it into a UIImage). Is there some way to make a CGRect and then convert it to a UIImage? Or is there some other way to make a simple black box?

推荐答案

根据你的情况，你可能只是使用一个将 backgroundColor 设置为 [UIColor blackColor] 。此外，如果图像是纯色的，您不需要一个实际上是您要显示它的尺寸的图像;您可以只缩放1x1像素图像以填充必要的空间（例如，通过将 UIImageView 的 contentMode 设置为 UIViewContentModeScaleToFill ）。

Depending on your situation, you could probably just use a UIView with its backgroundColor set to [UIColor blackColor]. Also, if the image is solidly-colored, you don't need an image that's actually the dimensions you want to display it at; you can just scale a 1x1 pixel image to fill the necessary space (e.g., by setting the contentMode of a UIImageView to UIViewContentModeScaleToFill).

尽管如此，看看如何实际生成这样的图像可能是有益的： / p>

Having said that, it may be instructive to see how to actually generate such an image:

CGSize imageSize = CGSizeMake(64, 64);
UIColor *fillColor = [UIColor blackColor];
UIGraphicsBeginImageContextWithOptions(imageSize, YES, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
[fillColor setFill];
CGContextFillRect(context, CGRectMake(0, 0, imageSize.width, imageSize.height));
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

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